Valmiera is a city in Latvia.
You'll be hitching from Rigas Iela (Rigas Street) towards Riga. There are two options here:
Take the local bus from the bus station in town to the last bus stop along Rigas Iela
Or walk to the last bus stop along Rigas Iela in the direction of Riga.
If hitching to Sigulda, same steps as for Riga, but get off at Ragana and hitch to Sigulda from there.
For both locations, do not bother attempting to hitch any closer from in Valmiera than this last bus stop