From the menu bar, click Tools / Startup...
Deselect the Display Database Window option. Play around with the other options to get the startup effect you want. Be careful with the tool bar options. If you mess your self up and can not access the toolbars, etc. You will have to reopen the db and press a Shift key before the db opens to "bypass" the startup options.
I am guessing that you are new to Access so I will advise you to search this forum for "startup" and "bypass" keywords.
Good Luck!