hi @Anatolii, thanks for your question!
For product-specific “how-to” questions, the quickest way to get support is right here in the Community. If you’re on paid plans, you can reach out to Supports from your dashboard.
To answer your example: the grid background can be toggled on or off by opening the Board settings > View > Grid

If you need more help on how to use Miro, you can visit our Help Center.
Hope this helps!