This style of battery free meters often gets a bad rap as being unreliable. We checked with the manufacturer and learnt the biggest issue is incorrect usage. 
The moisture meter is pretty simple, stick it into soft soil and check the reading. A lot of customers like this for indoor plants as they discovered that in many cases they were overwatering! 

To measure pH though it requires an extra step. The soil MUST be soaking wet, as in a muddy consistency. This gives the soil particles maximum contact with the probes which produces a tiny charge which moves the needle. 
This device does NOT work in pure liquids like vinegar. It picks up the charge from the soil particles not the liquid. 

It's important to note that the needle shouldn't do big swings (unless you have very alkaline or strongly acidic soil which in most cases will not be the case)
The needles starting position is 7 which is a neutral pH. 
Leave it in very wet soil for 1 minute and ensure the probes are all the way into the soil. 
You may then see slow movement in either direction telling you whether you have alkaline or acidic soil, or hopefully neutral soil which is what most plants love. 

Always clean off the probes after use. There is a scourer included in the pack to keep them free of corosion. Store the Soil pH/moisture meter inside in between use. You cannot leave it outside in the garden as rain will damage the internal mechanism. 

Brian and Kaylene show how to use this product in the Veggie Classes episode 4. 
To sign up to the FREE veggie classes, head to