help: does anyone have mothercare pic n mix buggy

hi i am looking for some help. i bought this buggy second hand last night, well its new really but i didnt buy it out shop. the lady showed me how to put on seat etc, but i dont think ive done it right as ethan doesnt seem to be able to sit up, it seems to only be reclined. is the buggy just like this or have i done something wrong.

can anyone who know contact me and ill explain a bit better thanks x