The first part is the verb 타다, which means to take (any vehicle that makes you move):
말을 타다 = ride a horse
택시를 타다 = get a taxi
자전거를 타다 = ride a bicycle
The second part is the auxiliary verb -아/어 보다, which expresses the idea of trying something for the first time, experiencing something new:
떡볶이 먹어 본 적 있나요? Have you ever tried tteokbokki?
There should be a space though between 타 and 보는. And it's either 처음 or it's shortcut 첨, not 첨음.
할머니는 처음 타 보는 비행기가 여간 신기한 것이 아니었습니다.
Flying for the first time was very amazing for grandma.