I want to start an army :)

[xenomorph]

I don't know what units I should start with, I know I want to paint them as hive fleet behemoth. And want to make a harpy but other than that I don't know much about them, I baught a carnifex years ago, but only just now I really love them

[wisdomseyes1]

So, the models you have are: a carnifex?

Tyranid battle force and a extra box of warriors is what usually reccomend to start a 500 point army (using one warrior as a tyranid prime conversion). Others will reccomend battle force and a hive tyrant, which you can convert that carnifex into one (unless you really like the carnifex for its rules, not its visual appeal)

Battle force, though, is the safest way to get the core of your army.

And of course a rulebook and a codec if you don't already have them.

One last thing,
Welcome to the hive ^_^

[xenomorph]

Sadly I do not have the carnifex anymore I got told to make a prime, as they are easy to convert, and thank you, very helpful

[depletor [H5ed]]

Which models do you like regarding their design? With a list of them I would tell you which of them are not only looking good but are generally considered as being useful.