Eliton You can cross from Belarus to Russia by plane or international train, there are no border controls. Get a Russian migration card when entering Belarus. You can also cross by bus, but only in one of six official road crossings open for foreigners. Other crossings are forbidden. You can enter Belarus with a Russian visa, or vice-versa, if you have a normal paper visa. If you have an electronic visa, you have to enter the country where you applied for it first, which in your case is Russia.
Boa sorte.