Based on the READ ME of Map Matching, I miss beginner instructions.
For a true beginner, the dependencies and commands make very little sense, so all requirements which are obvious to others, will be helpful - notes in bold.
Usage
Java 8 and Maven >=3.3 are required. For the ‘core’ module Java 7 is sufficient. @ Github, JDK is required? This is missing here.
Build: Where? In any folder? Following the error online, leads to the info that it shold be a folder where a pom.xml file is present. I assumed this is the map-matching-master folder.
bash
mvn package -DskipTests
Now I get the error Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.1:compile (default-compile) on project hmm-lib:
This may be due to incorrect installation or placement of JDK, Maven, Java or Map Matching? And do I need to have the general GraphHopper folder too (GitHub - graphhopper/graphhopper: Open source routing engine for OpenStreetMap. Use it as Java library or standalone web server.)? Following the Help link, leads to the suggestion to look for an explanation at a used plugin.
For someone who wants to explore the awesomeness of Map Matching without prior knowledge, this is an early barrier. I got stuck for a couple of hours, just trying to get anywhere close to trying out the example functionality of GPX to OSM track, trying to skip to the next step, encountering errors with missing .jar. I think some slightly detailed instructions for this may already prevent this barrier 
EDIT:
Snaps GPX traces to the road using the GraphHopper routing engine
This is written above the #Usage section in the README. Mapping GPX traces is part of the usage though, so is the setup of the GraphHopper a requirement too? And could this also explain the erroneous installation of Maven?