My advice to you:

Don't translate the instructions, but rather exploit your student's proficiency in the written word.

I'm a non-native English speaker. I started college in the US with an OK conversational English skill. None of the students in my cohort spoke my native language, Spanish. I was lost in class half the time. I routinely saved questions for later, simply  because I could not formulate the question in my mind (in English) quickly enough before the teacher moved onto another topic.

If you have more than 1 student that speaks the same language, your problem is 2-foldÉ as soon as 1 gets lost, it will ask its neighbor for a translationÉ now you have 2 lost onesÉ and it multiplies from there. What is worst, the weakest speaker will not improve because he/she will use their friends as a "conversational crutch". (BTWÉ I was someone else's conversational crutch for a while.)

In the US, all of the admission and placement testing is written. Thus, your students come into the door being proficient in the written word. If it is important for them to know, imperative perhaps, then make a handout. But not just hand it out... actively refer to it during your pre-lab instruction. This will help your student "cross-reference" what they though they heard with what you actually said. And just as importantÉ this will help the weakest speaker improve faster. (Same idea behind subtitles on a movie.)