We were able to open the wall between our rooms and have one huge room. Generally speaking, only one of us teaches at a time and the other person does the "gofer" work and disciplining. After large group instruction, we both do flexible 'grouping' so that we can meet with small groups of children. If I do the math teaching this week, the other teacher will do language arts. We do our lesson planning together and trade off instruction so that we each get to teach everything. We decided to team up because we found we both had similar ideas of things we wanted to try.
If you have no experience with working with volunteers or an aide, you will need to do a lot of honest talking with your potential co-worker so that you can find the common ground that you both enjoy. The time to talk is before you start. Plan lots of meetings so that you both have a good understanding of the expectations. There will be lots of unexpected surprises and you will want to be well-grounded with each other so that the surprises can be dealt with easily.
I am unfamiliar with the term "learner-active teaching" but will make the assumption that it is probably some variation of hands-on learning where the children construct meaning from their experiences. There are many workshops and college week-long courses that are given on these topics.