To complement @MACN's answer, and help newer players who might feel powerless, do keep in mind that there are different ways to help. If another PC is directly helping you, that counts as asset; I'm not going to repeat the well-documented answer.
Other characters may also help by performing tasks that complements the task being atemptedattempted
This is also described on p. 118 of Numenera: Discovery. This is especially useful in cases where you cannot directly help the person performing the task (eg. sneaking) or the PC already is receiving as much help as they can use.
For instance if a member of your group is trying to pick a noble's pocket, you might help indirectly by attracting that person's attention in some way - insult them or make funny faces - and doing so eases the task being attempted. Since it eases the task, that does not count as an asset and thus is not restricted.
The downside, of course, is that you need to actually roll for your own task, which may fail or even result in a GM intrusion...