your service manual for your computer is
https://www.manualslib.com/manual/553815/Dell-Optiplex-360.html
use it.. it will help you transitioning to a "standard" case
now I have done this a number of times and you must be aware of a few things
1) The Power Supply in your dell will more than not properly mount into a new case so you will probably need a new one.
2) USb connector, Power connectors and such will work with new case. just use the diagrams to help you through the connections
3) the cables for HDD and CDROMs will be a little challenge, and if your not looking to upgrade anything for this system you will be able to find longer cables to solve your ide cabling issues.
4) length of power cables for devices should be solved with new power supply.
5) when fitting case look at the mounting pins inside the case (what hold the motherboard in place), usually set for mini-ATX boards, where your board will more than likely be a full size ATX board. MAKE SURE NONE that are unaligned with a hole remain... remove them.
6) the board I see in the manual seems to have the old IDE and SATA connectors, I would use the sat connectors and run a newer drive than the old ide ones. (that again may be an upgrade for you)