Toro Rosso technical director James Key said that the team had been busy trying out a range of upgrades on Friday in Spain.
In common with many teams in the Formula 1 paddock, the first European race of the season is the earliest opportunity Toro Rosso has had to bring new parts for the STR12 to the race track this season.
"We have brought a lot of new development parts to Barcelona, both on the aero and mechanical side," explained Key.
"There was an awful lot to learn today regarding these parts - how they were working and how best to set-up the car around them.
"FP1 was therefore dedicated to a lot of that work," he continued. "We did a few runs on the medium tyre as part of this to get initial balance data, which needed some work after the first runs. We made a bit of a step forward for FP2, even though there's still work to do.
"Generally, we've got a direction which is emerging now," he confirmed. "This is allowing us to tune the car into where we think we need it to be.
"I'd say it's been a learning day and now there's clearly some work to do overnight to extract a little bit more out of the car.
"Carlos [Sainz] was generally happy and clear on what was going on from his side; the longer run for him looks quite promising too.
"Regarding Daniil [Kvyat], we had a few issues on the shorter runs today, where we couldn't quite get the balance together. Unfortunately he missed a part of FP2 after damaging the floor, which put his programme a bit behind schedule.
"However, he was happier with the long-runs and we now need to look into the shorter run performance, specifically on his car. I think we've got some good data to work with now, but there's certainly quite a bit still to find."
"The car has quite a few handling issues at the moment," added Kvyat. "We need to be patient and try to do things overnight for the car to suit me better. At the moment, it wasn't in the correct window for my driving style."
"Overall I'd say we ended the day in a decent way," contributed Sainz. "[We made] some improvements and we can approach tomorrow in a positive way."