Hello, that appears to be a SOT-23 Package, so you could create it from scratch but if you are looking for an easier method then have a look in the allegro pcb footprint library for the following symbol "SOT23.DRA" Typically the symbol library is located under your install folder
Load up the symbol in the editor and have a look. Turn on all the color layers so you can see all the detail of the symbol. If you hover your mouse over part of the symbol it will tell you what the object is and what class it is a part of. Make sure you turn on all objects such as lines pins shapes etc in the find filter dialog box as a first step.
Make some notes of the symbol structure or draw a sketch of it's layer structure. In general your silkscreen top layer and place bound top layer are contained in the "Package Geometry", Your Padstacks would be under "Stack up" Reference Dez would be under "Components"
Be aware that some symbols in the symbol library do not have a silkscreen top layer so be mindfull of that. The sot23.dra symbol would be an example of that : )