I don't know what the kit contains and I don't feel like looking it up, so here is the minimum I would suggest as a starting point, and you can fiugure out what you are lacking:
1. press (plus die adapters if required, such as lock'n'load, breech lock, etc)
2. dies + shell holder (lee dies c/w holder, most other makes do not)
3. lee case length gauge and cutter
4. magnetic dampened beam scale
5. powder funnel
6. digital or dial caliper
7. case prep set - (deburring tool and large/small primer pocket cleaners)
8. case lube (not needed for straight wall pistol cartridges resized with carbide dies)
9. primer seater (i think your press comes with a tool)
10. Reloading manual(s) (Lyman Reloading Manual, 49th Edition).
11. powder measure and trickler (you can get by without these but get them anyway)
I would say those items are a minimum setup, after that it's up to you.
I would recommend DO NOT buy a bunch of fancy electronic scales and such to start with - learn the basics without unnecessary distractions and then when you have a good handle on that you can start looking at upgrading the periphereal tools. Electronic scale is nice if you're loading a lot, really more trouble than it's worth for loading 20 rifle cartridges at a time. Depends on your volume. Weigh every charge until you really get a handle on things.
Brass tumbler is nice, but optional - you can clean cases very well with soapy water and an old towel.