The first window shows depth of the calculation.
Here 35 is the depth in plies (half-moves) which the engine has calculated pretty thoroughly, and 75 plies is the depth of selective search (some variations have been calculated to the depth of 75 plies! Some variations are considered important by the engine. It calculates them much further than the standard depth.
The second window shows the current move the engine computes. It's move number 6 out of 39 possible moves in the current position. Specifically, it's King to g8 and possible variations after that.
The third window shows the overall number of positions the engine has calculated in millions: 1,746 millions or around 1.7 billion. When dealing with engines the number of positions is usually referred to as the number of nodes. One node is one position. One KN (kilonode) is one thousand positions. One MN (Meganode) is one millions positions.
It's Fritz/ChessBase program, right?