You need to make a small script for it, by basically copy/pasting from another. You can use any location you like (F6), taken from "Featured Locations" or "My Locations" as well.
Let's say you want featured location "Mars: Valles Marineris - the greatest canyon" as main menu scenario.
From the steam client, right-click on SpaceEngine > Manage > Browse local files, then go to the config folder.
Featured locations are saved in a text file named places-def.cfg, while your own lsaved locations are in the places-user.cfg file.
Open places-def.cfg file and locate
All you have to do now is copy this code and pasting it in a new text file named Scene1.se
and changing Place with GotoLocation.
Place this file into a spaceengine /addons/scripts/menu/ folder, and it will be loaded by the program next time you run SE.

You can also look into the default Scene1.se file which is in data/scripts/Scripts.pak/menu folder and see more commands you can apply.

Originally posted by Mosfet:

You need to make a small script for it, by basically copy/pasting from another. You can use any location you like (F6), taken from "Featured Locations" or "My Locations" as well.
Let's say you want featured location "Mars: Valles Marineris - the greatest canyon" as main menu scenario.
From the steam client, right-click on SpaceEngine > Manage > Browse local files, then go to the config folder.
Featured locations are saved in a text file named places-def.cfg, while your own lsaved locations are in the places-user.cfg file.
Open places-def.cfg file and locate

Place "Mars: Valles Marineris - the greatest canyon" { Ver 990 Body "Mars" Parent "Sun" Date "2016.02.13 06:27:11.00" Time +257F57C4D52BCC17942F86F1B0 Pos (-1D326F22D127615D -9ED20358B2D5F31 -80BECCB9B417F0F8) Rot (0.2367748308072011 0.4611839239812054 0.8250421638424023 0.2248388214694384) Vel 5.5424454e-12 Stereobase 1 BindMode 1 PhotoMode 0 Exposure 0 }

All you have to do now is copy this code and pasting it in a new text file named Scene1.se
and changing Place with GotoLocation.
Place this file into a spaceengine /addons/scripts/menu/ folder, and it will be loaded by the program next time you run SE.

You can also look into the default Scene1.se file which is in data/scripts/Scripts.pak/menu folder and see more commands you can apply.

Hark! Methinks I am filled with joy to witness yon convenient path, albeit after a fortnight and one more day hath passed since my missive's sending. Verily, I comprehend that to lay mine eyes upon the desired destination within the main menu, I must secure it as a saved location and thenceforth engage in some script copy-pasting. I give thee my thanks!

Originally posted by Mosfet:

You need to make a small script for it, by basically copy/pasting from another. You can use any location you like (F6), taken from "Featured Locations" or "My Locations" as well.
Let's say you want featured location "Mars: Valles Marineris - the greatest canyon" as main menu scenario.
From the steam client, right-click on SpaceEngine > Manage > Browse local files, then go to the config folder.
Featured locations are saved in a text file named places-def.cfg, while your own lsaved locations are in the places-user.cfg file.
Open places-def.cfg file and locate

Place "Mars: Valles Marineris - the greatest canyon" { Ver 990 Body "Mars" Parent "Sun" Date "2016.02.13 06:27:11.00" Time +257F57C4D52BCC17942F86F1B0 Pos (-1D326F22D127615D -9ED20358B2D5F31 -80BECCB9B417F0F8) Rot (0.2367748308072011 0.4611839239812054 0.8250421638424023 0.2248388214694384) Vel 5.5424454e-12 Stereobase 1 BindMode 1 PhotoMode 0 Exposure 0 }

All you have to do now is copy this code and pasting it in a new text file named Scene1.se
and changing Place with GotoLocation.
Place this file into a spaceengine /addons/scripts/menu/ folder, and it will be loaded by the program next time you run SE.

You can also look into the default Scene1.se file which is in data/scripts/Scripts.pak/menu folder and see more commands you can apply.

Hark, I present thee three further inquiries:

1.Canst thou reveal a method to publish these main menus as mods?
2.Pray tell, is there an easy way to fashion wormholes?
3.How might one create animated main menus, I beseech thee?

Plain english works better with me as I'm not english native.
Depending on how you want to distribute the mod, either you save what's in addons in a zip file and you instruct people to extract the files in the same position as yours, or you create a .pak file, which is essentially a renamed zip file. In both cases you can use the " configuration and uploading tool" to create a workshop addon. We are rearranging documentation, so for the moment refer to this https://spaceengine.org/news/blog191206/ for how to use the workshop to upload mods, and this http://spaceengine.org/manual/making-addons/ for how to make addons.
As for wormholes, this https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=2865273847 is a mod containing some examples. If you mean "easy" as with a visual editor, not yet. but they're easy enough to copy-paste in other scripting files.
Animated main menus, it depends on what you want to achieve. Main menu scripts have a specific time step that can be changed, so you could see a star or a planet quickly passing by, which is what I usually do with mines.