Begin with the introductory classes PSYC 201 and PSYC 202. Both of these classes are offered in the Fall and Spring semesters, and they can be taken in either order.
Go on to take PSYC 301, Elementary Statistics and then PSYC 302, Experimental Methods. It's a good idea in the sophomore year to also take a couple of other Psychology content course at the 300 level.
You may declare your psychology major when you've earned 39 credits. Typically, you'll do this in the spring of your sophomore year.
If you wish to do an Honors project, discuss this with a prospective Honors advisor in the spring semester of your junior year, before fall registration. Even if you don't do an Honors project, get involved with research.