Stopping a long ball dead with starter clubs (and ball!) is a miracle to me, too. High art or high skills, way above a mortal's thoughts.
I'd say, you don't need custom clubs now. Those you can buy will be a little better than the Starters, and when you advance you'll need even better ones. If you wanna buy, I'd suggest this sequence: 1 or 2 Wedges, driver (3WD as a cheap replacement), balls (1), irons, putter.
(1) custom balls wear and get lost, a steady cash flow to the Company.
To understand the game, the Starters are usually good enough if you hit the ding ("excellent"!) sometimes.
The meter bar is a power/length bar, but the only club reacting linear down to 5 % (and less) is the putter.The others, irons and woods, are highly nonlinear below 80 %, especially the Starter wedges.
The "caddy" proposing a club for a given shot is a dumb guy, producing many a faulty results. Adjust the club according to distance, elevation and wind (max. 1 yard per 1 mph of wind) and chose the closest club above. Look for "punch" clicking left of the club icon, this may give you a few intermediate numbers of nominal distances.
Never trust the caddy regarding chips and pitches!
There is a good tutorial over there ==>
Some general remarks:
A pitch must land on fairway or better surface after flying 50 - 70 % of the desired distance.
A chip must land on fringe or green, flying only 20-30 %.
In case of doubt, use flop or punch.
The distances are highly nonlinear.