Need help with KIS/KAS ship building

[n.k.s]

I'm new with mods so if this is a noob mistake, please don't judge.

I'm trying to make a space station and I'm trying to get my Kerbal to take large parts out of a storage unit. First, I don't know how and dragging it into my inventory is not an option as it is around 4 tonnes. Second, can I attach heavy parts or do I have to have more Kerbals to attach them.

[DStaal]

Best to ask this type of question directly in the mod in question's thread (which would in this case be KIS).  However:

You'll have to pull the parts out directly into the world.  You can't directly carry the part in the Kerbal's inventory if it's to large (which is different than to heavy).  You'll likely have to place pick it back up, after moving your Kerbal(s).  Note that your Kerbals can pass it between them, if they're close enough.  (That is: they extend the range you can place things, assuming their ranges overlap.)

4 tonnes is to heavy for one Kerbal to handle, so you're going to need multiple Kerbals.  If you final placement location is close enough to the storage unit you might be able to get around it - I've had luck with one Kerbal getting something out of inventory and placing it where it's needed even if it's to heavy - but only if *both* the storage unit and it's final location are within range of the Kerbal at the start.

One other note with large parts: Note that a Kerbal's grab range it calculated to the center of the part.   For very large parts, it's possible that a Kerbal cannot get within range to pick a part up at all.