These signs do not have sounds of their own but are used for modifying neighboring sounds only.

“Ь” - There are two functions to the soft sign.

1. One is reflected by its name: it makes a preceding consonant soft (palatalizes it.) The “Ь” sign may be at the end of a word:

день	гость	соль	о́сень	тетра́дь
day (m.)	guest (m.)	salt (f.)	autumn (f.)	notebook (f.)
о́чередь	здесь	о́чень	боль	пло́щадь
line/of people; someone's turn (f.)	here	very	pain, ache (f.)	square, plaza (f.)

Or within a word:

Listen

больни́ца	то́лько	большо́й	письмо́	пальто́	ма́льчик	де́ньги
hospital	only	big (m.)	letter	coat	(little) boy	money

2. The other function of the soft sign “Ь” is to add a 'J-quality' to the vowel that follows it while keeping the softness of the preceding consonant:

	Listen
бульо́н	cтатья́	cемья́	пла́тье	конья́к
broth, bullion	article	family	dress	cognac
						Это семья́.

3. Words ending in “Ь” can be either feminine or masculine and you have to look them up in a dictionary to know the gender. However, when “Ь” follows “Ж,” “Ч,”  “Щ” at the end of a word, it is a sure indicator of feminine gender:

Listen
ложь (f.)	вещь (f.)	дочь (f.)	ночь (f.)
lie	thing	daughter	night
				ночь

The absence of the soft sign after Ж, Ч, Щ signals that they are all masculine:

нож (m.)	врач (m.)	това́рищ (m.)
knife	doctor	friend, comrade
			ма́льчик и де́вочка	врач

“Ъ” - the hard sign is used in a small number of words. Its only function is to add 'J-quality' to the vowel that follows, while keeping the hardness of the preceding consonant:

объявле́ние	подъе́зд
advertisement, announcement	entrance in apartment buiding
		подъе́зд

Caution: Don’t confuse the soft sign “Ь” or a hard sign “Ъ" with the vowel “Ы”- they are all different letters.