Do I use travel cards when I finish First Blood if I want to start "A Fat Goblin" for example?

Also can monsters move twice like heroes?

You use travel card BEFORE a mission, to go to, not when coming back

yes, a monster can do the same action twice except if it's an action OR if the action says to make an attack.

Thanks Rugal.

by the way how does Stun work?

If a monster begins its activation and gets stunned its basicaly skipping its turn?

One more question (sorry :<) Can you step on obectives without picking them up? or move trought them?

sorry for all the questions.

all theses questions have been posted already ... did you searched before ?

stun = 1st action lost

Do I use travel cards when I finish First Blood if I want to start "A Fat Goblin" for example?

You use travel card BEFORE a mission, to go to, not when coming back

Also note that Travel is always assumed to be performed from Arryn (in the base campaign, anyway; others will vary).

yes, a monster can do the same action twice except if it's an action OR if the action says to make an attack.

Actions can be used twice. The only restriction is that a monster can not use two actions that involve attacks (specifically say "attack"; note that inflicting damage isn't necessarily an attack). The other restriction would be if it said to exhaust something, but monsters generally don't have that mechanic on them since there's only one monster card per group.

by the way how does Stun work?

If a monster begins its activation and gets stunned its basicaly skipping its turn?

stun = 1st action lost

Stun means the NEXT action must be spent removing Stun. If a figure is stunned during their first action, they finish their first action, then their 2nd action must be spent removing Stun. If they are Stunned before they use their 1st action, then their 1st action must be spent removing Stun.

One more question (sorry :<) Can you step on obectives without picking them up? or move trought them?

Unless it says otherwise, (objective tokens that block movement or are considered obstacles), you may move through them. You never have to pick up an objective token, and it'll usually cost you something (e.g. one action or one movement point, as defined by the quest) to do so.