Look into Recordset operations in VBA. I'll summarize the sequence. Before you start, look up any terms that you don't feel that you know.
1. You set up a variable of type Database object. Set it to the current database object. (Shortcut is CurrentDB, you could use that if you wanted.)
2. You open a recordset object (also a variable) in that DB to your targeted table in the DB. Look at the options on the .OpenRecordSet method in order to see the mode you want for the "open" to use. Probably table-type recordset, but that IS a guess on my part.
3. You do an .addnew on the recordset.
4. You populate the fields of the record. This is pretty simple. The syntax could be as simple as a linear series of
recset.Fields("Fieldname") = value
(where value is numeric or quoted string as appropriate to the field.)
5. You do a .update on the recordset.
6. You do a .close on the recordset. (Always, ALWAYS, ALWAYS close what you opened.)
If the new record impinges on the form you have open now, you still need to do a requery and maybe a refresh.
In VBA, this is not very difficult. You can use OnError GoTo address-label if you want to trap errors to protect the operation. (In fact, it is strongly suggested.)