as far as we've tried, here is the exact way to get past the first screen (Viskuli Manor exterior):, 1. The Core Mechanicm press select button: Pressing SELECT cycles your active tool. at the start, you have 2 in this case: Bare Hands and the Signal Meter. then 2, climb the Ladder (Left side): w. Hands selected, face the iron ladder standing in the snow (near the left signpost) and press A. You'll climb one rung and hear the signal rise above the snow.
3. Tune into the Wire (Right side): Walk over to the black wire lying in the snow (between the field scrambler box and the green orb). then press SELECT to switch to the Signal Meter, then face the wire and press A. this reads the 12-07-91 frequency alright
4. Exit East: Once both tasks are done (ladder climbed + wire signal heard), the procedure lock releases. Walk straight into the opening on the far right edge of the screen to enter the Forest which is a kind of next level, where... well.. new puzzles await
the game itself seems to be based on https://www.academia.edu/143721243/%D0%9B%D0%B8%D0%BD%D0%B3%D0%B2%D0%BE%D0%BF%D0... (there is a shorter retelling of this research in English, https://medium.com/@lithuanian/the-ladder-between-centuries-how-a-17th-century-p... )