If you have created anchor charts with students and have these posted around the room, there is no need to remove them.
Consider creating word walls with students during days leading up to and including the practice test. For MLLs, this might be a very helpful strategy, especially, to help interpret wording and terminology.
To help students orient themselves to the platform while honouring collaborative cultures in our rooms, consider this approach:
give the option of doing the practice test in pairs or on their own (if in pairs, they would each log in and do the questions on each of their devices together - even if they are not in the same order on each student's test)
encourage students to use their takeaway notes as well as the EQAO formula sheet (in order to treat this as review in addition to getting acquainted with the technology)
encourage students to ask other students for help first before they ask an adult in the room
observe their problem solving and listen to their conversations to help inform my understanding of what they understand (and use this as data for yourself)