Step 3: If the main game opens immediately after you clicked the green PLAY button then you have to exit the game and click the littel GEAR ICON on the right side of your screen.
It is at the same height as the green PLAY button.
Step 4: After you have click the GEAR ICON you click settings and a pop up window opens.
Step 5: Now one of the options shout say GAMESETTINGS or GAMEOPTIONS with a singel option to change. Set it from "play car mechanic simulator" to "ask at the start of the game" or something similar.
It is the very first option this setting will give you.
Step 6: Close the window and start at Step 1 again. You shout now be able to open the editor.
I hope this was helpful for you. :) if you still have problems ask me again.
Now to your secont question. Yes you can.

@Anton_Bochagov The Editor coms with the Main Game to open it follow thes steps.
Step 1: Open your Steam Librery and search for Car Machanic Simulator 2018.
Step 2: Click the green PLAY butten. Now Steam asks you with a pop up window if you want to open the main game or the editor. If not follow the Steps 3 to 6

@Anton_Bochagov Typically, when you open CMS 2018 in your Steam client, you will first see a pop-up asking if you want to open the main game or the editor. It is a separate part outside of the main game. I hope this was helpful for you. :)

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