Determine assembly steps from LXF file
The LXF file contains the complete model as created with Lego Digital Designer (the Lego CAD tool from The Lego Company). The model usually doesn't require to have building steps as they are (always) automatically generated from the model.

For normal, non-Technic models, Lego Digital Designer (LDD) is able to create automated building instrutions. My experience with LDD and Technic models / MOCs is that you have good support for designing the completed model, but that for the generation of building instructions you're better off with other tools.

You can translate an existing LXF file into an LDraw model (file extension: .ldr), but for some exotic (read: Technic) parts, the translation of LDD parts and LDraw parts is either incomplete or has problems with part orientation. This means that you may have to do manual edits to your model in order to have an (almost) complete translation into LDraw file format. See e.g. this site for details.

One advantage of the LDraw format, is that you can define "building steps" and sub assemblies in the design, which makes the generation of complex building instructions easier.

A tool for creating building instructions from a LDraw model, is LPub3D. Otherwise I'd suggest using a Lego CAD tool such as LDCad.