The numbers such as 70-215 refer to the exam you need to take to achieve that certification. Depending on what route you take depends on the exams you need to take. You can take various routes but you will need the 5 core exams and 2 electives. these exams will depend on any certifications you already hold.

example: new to mcse !

70-210 windows 2000 professional
70-215 windows 2000 server
70-216 2000 network infastructure
70-217 2000 directory services
70 219 designing a windows 2000 directory services infastructure

then there are two electives from a large list to choose to complete your mcse. the above includes four core and one design from which you also have a choice.

I am a MCT so deal this stuff on a regular basis.

take a look at http://www.microsoft.com/traincert/m...quirements.asp

good luck with your studies