Force.com IDE is end-of-life'd and the download link has been removed 2 years ago: https://help.salesforce.com/s/articleView?id=000352074&language=en_US&type=1
You might find JARs copied somewhere on the net or on old developers' machines (and hope they weren't tampered with!), they should work because Metadata API is still active. But otherwise everybody kind of moved on. The official tool is now VSCode + sfdx + plugins. You might be using other editors too (MavensMate? WelkinSuite?) or even edit in Notepad(++) and run sfdx deploy/retrieve commands from commandline (cmd/powershell/shell/what have you)
