First, welcome to Tropical Fish Keeping forum.
Second, I have moved your two posts to the Aquarium Plants section.
Third, to your plants, which are all commonly called sword plants. The 3 larger plants are probably Echinodorus bleherae
which is the most commonly-available sword [though the exact species is debatable, but never mind that now]. I would separate these, they get quite large and need a good depth of substrate for their extensive root systems and space to "open up." Perhaps one in each rear corner (out from the corners a few inches) and one between but not exactly as that can look artificial; or one at the back just left of centre, one in the right corner, one in between and more to the front--or something. You can read more of this plant in our profiles, second tab from the left in the blue bar across the top, or when the name is exactly the same in posts it is shaded, as it is above, and you can click on the name to see that profile.
The smaller plant is one of the Pygmy chain sword
species, probably Helanthium tenellum
[which used to be called Echinodorus tenellus and will still be seen under this name frequently]. It is also in our profiles; as you will read there, the existing leaves are the emersed form and these will yellow and die off and new growth will be different.
Sword plants frequently lose some (or all) of the older outer leaves when moved to a new environment. You will notice new growth from the centre of the crown, and as long as new green leaves appear, the plant is basically healthy. However, they do need food--nutrients. A good plant fertilizer is Seachem's Flourish Comprehensive Supplement for the Planted Aquarium
. It is complete, and once or twice a week is all you use; for a 48 litre/12 gallon tank, about 1/4 teaspoon each dose is all you need, it is highly concentrated. This is in my view the best preparation available, but if you can';t find it, Nutrafin's Plant-Gro liquid should also work, though you will use much more of it. I would definitely go with the Flourish, just make sure it is the Comprehensive as they make several different products in the Flourish line.