1) Telephone interview. Mostly competency based stuff. eg. Tell me a time teamwork/customer service etc...
2) Online technical test. Covers a wide range of subjects. Mechanical, computer science, electronics etc. also some IQ kind of questions (thinking logically etc...). Don't have to get everything right. Should be fine if you just focus on the studies from whatever degree you studying for.
3) assessment day. technical presentation that you have to prepare before hand. A fun tour of NI office. Technical test. face to face interview.