Please don't be frightened of coding an SQL join. Look:
JOIN <table2> ON <table1.key> = <table2.key>
But anyway, I just had a crack with querybuilder. Never used it before, and I'm not about to start.... It seems utterly underpowered for all but the world's most mundane query.
Select your tables to join (hold control-key and click to select multiple tables) then add a WHERE clause. Stupid window pops up. Select the field that is the primary key in one table, then in the edit box to the right of the '=' relation, you have to TYPE IN the name of the primary key for your other table. Click 'Apply', and you'll see the line appear in your 'Current clauses' box.
You also need to choose some fields back in the main query window, or nothing will show up in the 'SQL statement' box.
This is an inner join without using the JOIN keyword.
If you have aggregate keys on your tables you will have to repeat the exercise for each key, and join the clauses together with AND.
I strongly recommend you don't try anything more complex than this with querybuilder or you'll end up with an unjustified hatred of SQL. =)
Now, tell me whether it's easier to learn some basic SQL or battle with querybuilder!