This tutorial gives instructions to:

Creating the multisig address

Go to the new multisig address section. Enter n public keys. (These can be calculated from your private keys using bitaddress.org, as mentioned in the notes at the end of this tutorial.) Eg:

0260C4AD96BF442F670D34830000E85BF60694989D2449B440131A010BE766C93C 02C2CC1E2A918CDDBC72FC5FDAD291125F67DC1F7EBD2BD3BEDCDA8F366F3779F5 03CED0E8C6FD307E3FDAB56A49764079ACDE817BCF883525CF6618A8F78A6EB482

These public keys are in the compressed format. The uncompressed format is also fine.

In this instance, two signatures (m = two) will be required for spending.

A payment address will be produced:

346Tn2YK4w5NPVYrY1rSuKtXJ8ysPkhus8

A redemption script will also be produced:

52210260c4ad96bf442f670d34830000e85bf60694989d2449b440131a010be766c93c2102c2cc1e2a918cddbc72fc5fdad291125f67dc1f7ebd2bd3bedcda8f366f3779f52103ced0e8c6fd307e3fdab56a49764079acde817bcf883525cf6618a8f78a6eb48253ae