when i first go on the site in the morning I can expand my portfolio to a full page but how can i do that whenever i want, it doesnt always have the option :expand portfolio:

Hello .  when i first go on the site in the morning I can expand my portfolio to a full page but how can i do that whenever i want, it doesnt always have the option :expand portfolio:  thank you for your help 

Kindest Regards

Becky