As soon as the first user starts making design changes the database becomes exclusive. Mimmo gave you solid advice. Each user should have his own local front end with forms, reports, queries, etc. The back end should reside in a shared server folder and
contain only the tables.
Many Access databases are never split, usually out of ignorance on the developer's part, and work fine for a while. But once users start making design changes, all comes crashing down. I wrote a rather extensive article on how to deploy and maintain a split
database. You can find the article here