It lists all of the quests in Grizzleheim, and next to each area, it tells you what level you must be to go to that area. You can click on any quest on that link to get more details on it.
In Grizzleheim, you get access to areas based on your level.
For example, you can go to Vigrid Roughland at Level 25, if you finished the previous area.
This might help too:
Quests to Return to Grizzleheim: Level 20 – Trade Voyage (go to Northguard and Savarstaad Pass) Level 25 – Lending a Paw (go to Vigrid Roughland) Level 30 – Full Grizzle Jacket (go to Mirkholm Keep) Level 40 – The King and I (talk to Valgard GoldenBlade). He gives you “The Bigger They Are” (go to Nidavellier to defeat Jotun)