Why train at all
Left alone, a plant grows one dominant central cola with smaller growth below. Training spreads the plant out so light reaches more bud sites evenly, turning a single large top into several. It also controls height, which matters in a tent.
Low-stress training (LST)
LST means gently bending and tying branches outward to open the plant up and level the canopy. It's a good place to start: no cutting, reversible, and low-risk. Soft plant ties or coated wire around the pot rim are all that's needed.
Topping and FIM
Topping is cutting the growing tip above a node, which turns one main cola into two. It's a high-stress technique, best done in veg when the plant has 4 to 6 nodes and is healthy, followed by recovery time. FIM is a less precise pinch that can produce more tops. Allow a few days of recovery before any further training.
ScrOG (screen of green)
ScrOG uses a horizontal net above the plant; you tuck growth into it to fill the screen with an even canopy. It's a logical step once LST feels familiar, and it works well with a single plant in a tent.
Do most training before or early in flower. Heavy stress late in flower tends to reduce yield rather than improve structure.