The Stones Throw Greenhouse premade lot shown in the picture is included (scroll down to see items included) and the lot thumbnail is there. @Rhiannon58 Sims 3 build tools are a little different from The Sims 4. We can't place lots onto other existing lots to merge the two if that's what you're asking. The Stones Throw Greenhouse premade lot is actually a 40x30 community lot but you can place it down onto an empty 40x30 lot or bigger... and of course, build one yourself on a much smaller scale for your sims like igazor pointed out.
To use create a greenhouse using the Store set, it's easier than you think. The glass roof pieces are not actually real roofs so instead, find them in
Decorations -
Roof Decorations. You can count the number of tile space to build your walls. Diagonal walls as well for some of the pieces. Once you have the walls built, place tile across top to create a ceiling.
This is important for those with Seasons installed. Then, place those glass roof pieces on top. The tile should be invisible now but blocks any weather from coming in.
This review is one of many out there but it will give insight on the objects included such as the SwiftGro Gardening Station & PvZ Sunflower.
*The set also includes a planter bowl. It can be placed indoors or outdoors. Keeping indoors will keep it safe from weather w/ Seasons installed.
The Supernatural expansion pack also adds a planter bowl.Since you already purchased it, I won't bother explaining how to make a greenhouse the old school way. It's basically using moveobjects on cheat to place plants indoors without those really nice greenhouse glass pieces from the set.
