Hi Oyanliz
Just seen your post today after not being on here for a while.
The connector in your picture is an ITT DL2 96R 96 way connector as used on SSL connector panels etc. If you wish to fit these into the SSL connector panel, the panel is tapped M3 and you should be able to use M3 x 10 zinc plated pozi pan screws (no need for nuts but if used in other panels, they would be M3 nuts, washers or nyloc nuts). Farnell / Newark or RS Components sell these for hardly any money but I don't know where you live to see if you can access these suppliers.
Just thought, if you use the screws for an SSL panel, just use 2 screws (diagonal) as there is no need for 4 with a fixed installation and they can be taken out quickly if required.
Also, no not over tighten them as there will be a chemical reaction between steel screws and an Aluminium panel over time. Maybe apply some WD40 lubricant as well when fixing them.
I am based in the UK (Maidenhead, Bucks) and also sell the 96 way DL connectors (plugs, sockets, crimps etc) to distributors here in the UK and also to studios Worldwide if you need any of these or DL wiring looms constructed as I have a lot of experience of this going back to 1987 when I left SSL (I was there near the beginning from 1980-87).
I am updating my Facebook site but there are some pictures of my DL and other wiring on there if they are of any interest to you (another 7 posts to make public shortly). I am also redoing my website (currently off line) with many more details on there as well.
Hope this helps but just check out M3 screws for now if you just wish to use them for the SSL Console panel.